19661377069 has 2 divisors, whose sum is σ = 19661377070. Its totient is φ = 19661377068.

The previous prime is 19661377019. The next prime is 19661377091. The reversal of 19661377069 is 96077316691.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19418422500 + 242954569 = 139350^2 + 15587^2 .

It is a cyclic number.

It is not a de Polignac number, because 19661377069 - 2⁷ = 19661376941 is a prime.

It is a super-2 number, since 2×19661377069² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19661377019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9830688534 + 9830688535.

It is an arithmetic number, because the mean of its divisors is an integer number (9830688535).

Almost surely, 2^19661377069 is an apocalyptic number.

It is an amenable number.

19661377069 is a deficient number, since it is larger than the sum of its proper divisors (1).

19661377069 is an equidigital number, since it uses as much as digits as its factorization.

19661377069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2571912, while the sum is 55.

The spelling of 19661377069 in words is "nineteen billion, six hundred sixty-one million, three hundred seventy-seven thousand, sixty-nine".